UnitedHealth's Bright Bet on Brazil

The managed-care giant's $4.9 billion purchase of 90% of Amil Participacoes represents an "excellent opportunity for UnitedHealth to grow in a new market."

Investors are cheering UnitedHealth's near $5 billion investment in Brazil—and for good reason.

Before Monday's opening bell, UnitedHealth Group (ticker: UNH) said it will buy 90% of Brazilian insurer and hospital operator Amil Participacoes (AMPIY) for about $4.3 billion in cash. It expects to get regulatory approval from Brazilian authorities this quarter to purchase 60% of the company from controlling shareholders, followed by a tender offer to buy the remaining 30% from public shareholders in the first half of next...